Understanding the nature of the kinetic process in a VO2 metal-insulator transition

• Published in: Physical review letters 2010-11, Vol.105 (22), p.226405-226405
• Main Authors: Yao, Tao, Zhang, Xiaodong, Sun, Zhihu, Liu, Shoujie, Huang, Yuanyuan, Xie, Yi, Wu, Changzheng, Yuan, Xun, Zhang, Wenqing, Wu, Ziyu, Pan, Guoqiang, Hu, Fengchun, Wu, Lihui, Liu, Qinghua, Wei, Shiqiang
• Format: Article
• Language: English
• ISSN: 1079-7114
• DOI: 10.1103/PhysRevLett.105.226405

Understanding the kinetics during the metal-insulator transition process is crucial to sort out the underlying physical nature of electron-lattice interactions in correlated materials. Here, based on the temperature-dependent in situ x-ray absorption fine structure measurement and density-functional theory calculations, we have revealed that the monoclinic-to-tetragonal phase transition of VO2 near the critical temperature is characterized by a sharp decrease of the twisting angle δ of the nearest V-V coordination. The VO2 metallization occurs in the intermediate monoclinic like structure with a large twist of V-V pairs when the δ angle is smaller than 1.4°. The correlation between structural kinetics and electronic structure points out that the structural rearrangement is a key factor to narrow the insulating band gap.